Telephone system



Dec. 26, 1922. 1,440;ll3

C. SPARKS. TELEPHONE SYSTEM Dmslmu. FILED MAY 15. I916.

2 27555 55. wen 1271". /9.d Ifiaries 5051155.

Patented Dec. 26, 1922.

e1Deb 'l iliilm'S -Tfim li .S "e pisre'nrr one-rice;

a: 'SUBQLYE'GOWYJ smemwi Application flea x5 15; 19I6.Serial ms 97.512: Renewed Auzustll. 1922. Serial m. 581.262.-

an em ierp of. 51 newiajnd improi'ed 511$ test; fol In mul- 3 replacing his-'rceivlerf iinfnediately removes the busy test. so that should the operator who established: the-l" gqnli'qqtiofi fill or be slow to disc ojliiect the calling-- line 3 from the link circuit thesaj'dijczillihg line is immediately rendered non -busy -yeir'r though the {answerng' rgilg of thedllffilllilll c rcuit-remains")- serte I in' the jack. Thesubseque' 'tinsertion of zLplug; into the multiple jack'of the line as a celled line. again briirgS-rbout the re-estnbli shrnent' of the busy test and elso open ates means in the first connectedlink eirc'uit to disass ocia te the said first jack of the line.

These and other objects of my invention will be mom particularly pointed out; in the ensuing specification and in the appended claims. v

Fore more complete understanding of my invention reference may be had to the 'acc'ompartying drawing in \yhich I show a well known common battery substation A connected by the line limbs 1 and 2 to a. line rircuit L. A double wound line relay LR controlling the line signals S is controlled over the limbs of the line circuit L. Multiple jacks J are provided and in the present embodiment of my invention :1 line signal S is provided for each jack. the jar-ks beirug distributed among difi'erent operetore.

l inlr the has its windings included in a-closed-cii-- cu ltu Qn-Ienergization of the but-the I-elaLy CO bei ditf i-entisrlly' wbund does lihe-relay-LB op rziti vely en ei-'gize;inntilan;.answering' plug-1s inserted in o ie ofih iniil- 'operacivly energized; The 'ope'i iitiye energi'z gtioh "of relay (IQ-causes the? circuit thereby restoring and eit'aeing the line signals Sj. i

The c'ord circuit- I r mg'p'Iug AP'and a calling plu GByth eftwo plii'gs Beingconnected by the heavily marked conductorsB-and 4 Wl1ieh ha-ve conden sers K andi K in'terposedi Associated' viitli the qnswering end offcord circuitC is '75 the" an wefin sIei'e-"supeijriso f x-eleg AS which; is energized m series with the.'resistapt-e 14 and operates to connect the operators SltO'tothivcord cond-i' ctorsfi unti -l.

The resistance 14 is arranged so that the first-o erz rtor to answer the 'eeill seizes itto tlie 'exelus'ion of any subsequent operator tl ututtemptsto answer the san' e c'ulh That is, when the first plug: A Pis connected to the calling liue the sleeve-relay associated therertilh is directlyconnected'to the sleeve conductor and-should a second operator attemptto seizetliis call the high resistance ot-the-windingM of th'e secondeord circuit prevents thesleeve relay of the second cord from receiving sutiicient energizing current (due to the shunting: effect of'the sleeve-relay of'the first link circuit) and thereby prevents the second operator from connecting: with the line. An answering tip'sii 'aervisory relay AT and an auxiliary tip supervisory relay AT are also provided. said' relays AT and AT and the sleeve'supervisory relay AS eontrolling the lighting of an answering supervisory lamp All. 1' also proride a recall relay RC energized when a eallin; subscriber replaces his receiver. and when the subscriber recalls the relay remains locked up to connect an interrupter to bring about the flashing f the said'lzimp .rli. busy test l'PIElUYElMI relay HT is: also hrovirled and is energized upon the operaony liige, the 55 G coin-prisesan answer- 70 tio of the relay RC, the said relay BT removing the busy test from the connected jacks when a calling subscriber replaces his receiver to immediately make the calling line available for connection as a called line. I also provide a link disconnect relay LD which is operated when a second operator connects to a line as a called line, that was lastused as a calling line before the first operator has disconnected the answering plu therefrom. The function of the relay LD is to operatively disconnect the apparatus-ofthe link circuit from the line. A a recall key RE is also provided which the operator actuates to seize a recall to connect her operators set 0 and which actuation 'also opens-the circuit of the relay RC which inturn opens the circuit of relay BT allowing the busy test .to be again placed upon the sleeve ofnthe jack. A meter relay MR 7 is --also provided ;,which actuates when the operators. set C is connected, the said relay in ;tur'n operating the meter magnet Mill once; to register ,a connection. The relay MR closes a locking circuit for itself to prevent further operation of the meter magnet should the calling subscriber operate his switch hook, and remains in such locked position until the operators set is disconnected from the cord conductors.

Associated with the calling end of the cord circuit C I show a calling sleeve supervisory relay (1S and a calling tip supervisory relay CT, the two relays controlling the li htiug of the calling supervisory lamp CL. Tfie relay CS,;upon actuation, disconnects the operators set 0 from the cord conductors. A ringingcontrol relay RCR is also provided which is operated when one of the plungers of the party line ringing key RK is depressed, due to the end springs of the ringing key RK being momentarily closed, the said relay then closes a locking circuit for itself and operates to connect ringing cur rent to the called line. Ringing generators Ur, G, G", and G are shown connected to the interrupters I, I I and I to supply interrupted generator ringing current as is well known in the art. A ringing trip relay RT is also shown which is operated when the called subscriber removes his receiver in re sponse to a call, said relay opening the ringing cir uit to disconnect the said ringing current should a subscriber remove his re ceiver during either a ringing period or a silent period. I also provide a non-inductive winding \V in multiple with the relay RT, the said winding NV being used on the two low frequencies of ringing current. The winding is controlled by the ringing key RK and is not used on the high frequencies as will be more fully described in the ensuing spccilication.

To the right of the drawing 1 show :1 called substation l) runner-ted by the line limbs 1 and 2 to a line circuit L similar to that of L and bearing the same reference characters but with the suffix prime added.

Having described in general the apparatus embodying my invention, I will now describe more in detail the operation of the system as illustrated. Assuming now that -the subscriber at the substation A initiates a call, the removal of the receiver thereat closes an energizing circuit for the line relay LR traced from round through the winding 5 of line relay llB, normal contact 6 of relay CO, line limb 2 through the substation A, line limb 1, normal contact 7 of relay C0 and through the winding- 8 of the line relay LR to battery. The closing of alternate contact 9 .upon energization of line relay LR, brings about the lighting of the line signals S. The closing of alternate contact 10 of relay LR places the busy potential upon the sleeve of the multiple jacks J associated with the calling line, the busy test circuit being traced from battery through the winding 11 of relay CO, alternate contact 10 of relay LR to the point 12. Here the circuit divides, one part extending to the sleeves of the multiple jacks, and the other part extending throu h the Winding 13 of the relay CO to ground? The busy potential is placed upon the sleeve of the multiple jacks J immediately upon the initiation of a call so as to prevent another operator plugging into a multiple jack of the calling line after the receiver at the calling substation has been removed. The re.-

i lay CC does not operate clue to it being ditl'erentially Wound but remains at normal. An operator noting the lighted line signals F now inserts the answering plug AP of :1 link circuit C into answering jack J of the calling line, thus closin a circuit for the sleeve supervisory relay 1 S, traced from battery through the winding of the relay AS, the resistance 14, the conductor 15, normal contact 16 of relay BT, normal contact 17 of relay LD, contacts of the connected plug AP and jack J and through the winding 13 of the relay CC to ground. The battery passing through the winding 13 of relay CC to ground imbalances the said relay CC allowing it to operatively energize to open its normal contacts 6 and 7 thereby interrupting the circuit of the line relay Lit, which relay restores ellacing the line sic' nals S. The relay AS supplies the busy potential to the multiple jacks (T of the call ing line. thus making them busy against in coming calls. The closing oi alternate contact 78 of relay AS clors locking circuit for itself traced from battery through the said relay. alternate Contact T3. onduc' tor T9 and normal cont-Art 16 to ground through winding 13 of relay (it). The re lay AS remains in locked position until i'liscouncction takes place.

The closing u normal contacts 24 and 25' of relay GS, conductors 26 and 27 'tothe Sleeve conductor-4 and to the tip conductor 3 oft-lie oord circuit CL Beforeiproceeding'further with'the description of'theoonnectiou; I will refer briefly to the arrangement'forexcluding 'operators who may subsequently attempt to answer the call from thesaid' line Assumthat a; second" operator inserts a rAff'into anothe'r iack'J ef-this calling ine, SllbSQqliBIltflZt tlxe mserneu of the first plug,

lug

this secondoperators "lephone will not be coiinected t6 the calling line; due to the fact tailgate ig essens-win ing 14 of the second ,cord"i's" connected" in -mu-1ti le with 0nd cord aha prviasnr from actuating thereby preventing the operators set' oflf the second cord" 'Ciidll'l't' from "being connected to the calling line."Tlfe"sec6tid-op erator not recei ingEan reply' tofli er' ihquiry knows that the cal has 'been silzed by another operator'. Again taking 'tl1e first connection; the closm era-mane contact 30 of relay AS estab islies-"ianenergizingcircuit for the tipanswering-supervisory relay AT, traced from batteryfthi'ough' the upper wiuding'of the relayA'P, conductor 31, normal contact"32 of'relayfLD;-sleeve contacts of the connected lug-and jack through the substation, back is roitghlthefip contacts of the connected; jackfand plug'normal contactj33 of relay DD," the alternate con-tact 30 of relay As' and through the lower winding ot'jthe relay AiT to, ground, The closing of alternate contact '34 of relay AT closes a circuit for the relay AT traced from battery through the winding-of the said reilay AT to ground at alternate contact 34 of the relay AT. The opening'of normal contact 35 of relay A'I 'prevents the li htin c of the answering supervisory signal AL.

lhe closing-of alternate contact 36'of relay AT establishes an energizing circuit for the meter relay MR, traced from ground at normal contact 37 of relay through conductor 38, alternate contact 36 of rela AT. conductor 39 the normal Contact 4 vi relay MR the Winding of relay MR. conductor 41. the alternate COfliZiHl 19 of rela v 3. conductor 23, normal rontact 25. conductor 43, through the lower winding of relay (T to battery and ground. The meter relay Mil. upon energiiing. closes a locking circuit for itself. traced from battery through the lower winding of the relay ("i1 :ductor l3. normal C ntact '1 conductor alternate rout-act 19. conductor 41 through the winding of the relay MR to ground at alternate contact'45 *oi 'rela y MIL The closing of alternate contact 46 of relay energizesthe meter magnet and causes it to operate its mechanismto register one call. The meter relay M ll remains locked up as long as the operators set is connected to the cord circuit so that the subscriber at the calling substation A in flashing his receiver will not operate the meter magnet MM; to cause the meter to again register.

The operator now inquires the wants of the callingsubscriber, and assuming 'it is the substation D, thesoperator-test-s the nulltiplejack of the called line in the usual inantier; and" if busy receives the usual busy click. A'ssumingtliat'the-called line is idle, the operator inserts thecalling plug UP into the jack-of the wanted linebringing about, the operation of thecalling' sleeve supervisory relay CS and the cut-offrelay U0 of the line circuit L over-a-circuit-traced from "battery through the winding of the relay Us; conductor-47 the-sleeve cont-acts of the connected plug and jack, through theupper winding 13 of the relay G0 to ground. The opening of the normal contacts 24 and '25 of the relay CS brings about the discon- Iiection of the operators set-O from the brings about the lighting of the calling supervisory lamp CL the circuit being traced from battery through the said lamp conductor 90, the normal contact 5]. of the end springs of the ringing key RK. conductor 52, conductor 57, normal contact 58 of relay RC, conductor 48, normal Contact 49 of relay CT, conductor 73 and conductor 50 to ground at alternate contact 37 of relay CS, the lamp remaining lighted until the called subscriber answers The operator having inserted the plug CP into the jack of the wanted line now depresses one of the plurality of plungers of the ringing hey llK. The depression of one of the ringing key plungers momentarily operates spring 51 of the end springs of the ringing key RK. The momentary operation of contact 51 01 the end springs establishes a circuit for the ringing control rcla R R. traced from battery through the winding of the relay RCR conductor 91. the momentarily clo ed alternate contact 51 o? the end springs. conductor 5'2, conductor 5L normal ronlact 58 of relay RC. conductor 18. normal contact 9 of relay CT. conductors T3 and 50 to ground at alternate contact 3? of relay (,i The relay RUE then closcs a locking circuit "For itself traced from battery through the wind: ing of relay PPR, norma contact of relay RT. conductor 5:1 the alternate c n tact 56 of relay RC. condu tor 57, normal .60 of relay RCR, the tip conductor, tip contacts of the connected plug and jack through the call bell and condenser of the called sub- .station D back through the sleeve contacts of the connected plug andjack to battery and ground through the alternate contact 61 of relay ROB. The call bell of the called substation isthus intermittently rung due to the current being interrupte bythe interrupter P. The calling subscriber receives the. audible tone being traced from the generator G, through the interrupter I conductor 62, resistance 63, the alternate contact 28 of relay RCR, conductor 29, over the tip conductor of the cord circuit, the normal contact 33 of the relay LD the tip contacts of the plug and jack. through the substation receiver back over the sleeve contacts of the connected plug and jack, the normal contact 32 of relay LD, the sleeve conductor t of the cord circuit conductor 26, conductor 43, through the winding of the relay CT to battery and ground. The noninductive winding W which is in multiple with the winding of the ringing trip relay RT is only connected to the low frequencies of the ringing current, say the 16 and 33 cycles of current. Should the operator have depressed a ringing lre i plunger to connect the ringing generator I which We will say is the generator delivering 16 cycles ringing current, the said current will pass through the interrupter I, through the closed contacts of the ringing key plunger to the point 95, the current dividing, part passing over conductor 96, the resistance winding \V, conductor 97, through alternate contact 60 to the call bell at the called substation and back to battery and ground at alternate 1 contact 61 while the other path is through the normal contacts of the other ringing l-zey plungers over conductor 66 through the winding of relay l 'l over conductor 97 and through alternate contact 60 to battery and ground at alternate contact 61 as above described. lVithout th s resistance W, should the low i'rvcpicncics as 16 and 33 cycles pass through the relay RT. the said relay would chatter and there would he a liability of opening the locking rircuit of the ringing control relay RCR which would bring about the premature disconnection of ringing current from the called line. The winding W In multiple with the winding of relay RT prevents this chattering of the relay RT. The winding W is not used on the two high frequencies, say and 66, due to the high rate of alternation of the high frequency ringing currents and the relay RT does not therefore chatter. With the arrangement above described I am able to obtain a posi tive operation of relay RT thus making the trip operation most positive in its operation, Heretofore it has been practically impossible to build a trip relay through which the different cycles ofringing current could be fed to the called line that would work not only on short, low resistance lines but also upon long, high resistance lines. But, by shuntng part of the current around the trip rethat it does not chatter ,on the lower frean audible tone notifying him that the called .q subscriber is being rung, the said circuit for uencies.

Should the called subscriber at the substation D remove his receiver during a ringing period, the combined generator and battery currentfrom the generator G and that .of battery 65 bring about the operation of the relay RT over a circuit traced from the generator G throu h the closed contact of the ringing key K, the conductor 66,

through the winding of the relay RT, alternate contact of the relay RCR, the tip contacts of the connected plug and jack through the now closed contacts at the substation I) back through the sleeve contacts of the connected pluor and jack, the alternate contact 61 of relay CR to battery 65 and ground. The combined generator and battery flow through the relay RT brings about this energization of the said relay RT causing it to open its normal contact 54, the opening of the said contact 5a opens the locking circuit of the relay R CH, relay RC1?- restoring to normal preventing further ap plication of ringing current to the called subscriber's line. Should the subscriber at the substation D remove his receiver during a silent period, an ener izing circuit for the relay RT is established from ground through the contacts of interrupter If, the alternate contact of the ringing key Rh, over the pre viously described path to battery 65 and ground, the relay RT energizing opens the circuit of the relay RCP. Thus l provide a method by which ringing current is instantly disconnected should the subscriber remove his receiver either during a live or silent period. Upon the restorat on of the relay RCll. an energizing circuit for the calling tip supervisory relay ("l is Pedal lishcd The circuit for relay UT extends from battery through the lower winding of said relay (IT, condurlor 4-3. wnductor 26,

lOO

f lhe st rbsciflbe'r at the jzallin substation A andthe 'siihs'ci'iber at that 1123 sntaaaen'n' are noyv in conversatlilhailtgfiditilthiasaid ta l ifihgg "cildll ifbitig traceltl" overthe' heavily nr'rarked cnhduetors;

Assumin tl atthes bjs'crihef's at the sobnisheli'fionversation, theisnlis'cif-iheflatthe s'iilistation inreplac ingf hifs ceiy'ennpon the svlritch' hook 0 "ens e at, se t qpeziiingits hont'a etfi l allow relayfh 'l}; an emia. The Ibsm cf the norina lfcdiitact" siblin s ahohtftheglighting ofithe answering AL over afeirciiiti 'acecl from'battery through the lamp alternate to' tacti69 oft'relay AS, colitliichor 7010' grouiill fiat arm-a1 contact 35 "'The tlosing of 'iiprnial j contact 35 also bi'ings about the' encrgilzation of the recall relay the circuit for relay RC being trace cllliroin battc through 'thllower winilmg t th relay l'f 0,7 .thef alternate contact GQ 'QffIlay A'Sand conductor 70 to round at h'orr n'alfcontact 35. The. relay RQ, 1 pon energizing,'closes a locking ciruittor itself traced from battery through the upper winding of therelay RC, its alternate contactT'f l, normal contact72 of the T892 key RE, conductor 73, and conductor to gronncl at alternate contact 37 of relay (-S.

The'closingof alternate contact 74 of relay RU establishes an energzins: circuit for the busy test.removing relay'BT traced from hattery"throuehthe Winding of the said relay BT. con'cluotor 75. alternate contact 74 ollsai rl relay RC normal rontactlfi of relay AT. conductor 73 and conductor 50 to gromrdat alternatecontact S7 of relay CS. ThertxlayBT upon energizing. opens its normal contactlfi. removing; the bus po tentirl from the sleeve of the jack. ot the alling line. \Vith the ahove-mentionedarraneernent upon the replacement of the receiver at the substation Afthe hnsy potential is reinorerltroni the connezterl jack so that Sl'lOlIld. an'operator wish to. connect with one of ithe 1n'i1ltfple jacks of'thesubstation A sheinaydo so Without receiving a busy sir nal sho d' the ,answering pla AP still ze wi'sh'to recaill befone disconnet on -has ta-ken place;* the" remov l of the receiver at 'the ss sfibstation' A-aga1n-b i'ings about the enen: gizatioh of theernays AT annu ty Th relay Aw ugain energiiitigfldee to they clos "clf the switch- 1ml: reentaetsa aflah are .llihg suhsciibers silhstatiori A; "closes t circt iit for relay' 7P1;- when relay' then' energizesaslhefore lescflbed :55?! i a circn-it "traced from the interrupter 1' through ante nate contact 80 =Qf relayRC, alternate 'c'ti tact"-35 ofrlay ATfimontiuct0r'70,"'and' alternate contac't' 69 o'fgrelay- AS throhgh'thelaitrpA Dtobattery. -'The' larnp is thn sfla shefl due to 'theconne'cte dinterrenter-{B tches notil-yingthe "operato'rgof the cord circriltCWhat the siib'scriber at the substation ,A is recalling. Upon the actuation "of relay A P "its normalcontact -76 assumes its alternate position opening the energizing circuit of the relay ET. The relay BT, npon' restoring, 'closes its'znormal contactlfito immediately place the*busy potential upon the "multiple'ja'cks (it the 'recalling line, thus making the said jacks busy thereby preventing another operator from plugging into a-multiolc jackof the recall- 'ing line. The operatorthen actuatesthe rec'allkeyRE toconn'ect her operators set O to'the cord conductors an'd thisactuation of the'key REfopensr normal contact'72of said hey thiis'opcning the energizing circuit of thcreeallrelay EC The opening 'of alternate contact' SO of relay RC frlis"onmeets the interrupter" T thereby preventing the further flashing of the answering supervisory lamp AL. The operation' of the cord circuit in estahlishing another con nection after an operator has seized a-recall is the same as previously described At the termination of conversation the display cif'the"two snper isorysignalsAL an'd'GLnotifies theoperator of the-termination'o'f the. conversation "and'she thereuponilm i illie 1. itseltiatnewdiau m he ,a i i g.p sLAt".a the calling ,plug from' the connected jacks. 'llhegrelays ASaud CS now restore to normahumd the cord cirrngit is now "available i for;establishing; other corinections, Should the QI LWl/Qd plugs remain the 'jack's of h mnne e li e afi he um i io f. qnve t at qe me as ever etw i mo edv vm -tlw a k off-c l i l n nd, quld i npthenl epe etoe inse a s es mn tie eij e ls; pfaltl i se i r 'eii a e es Pu po es ti h ma tian tth s wed Pl intQ- e mi tii l i-iesk of the-l n e i about the ienergiz ation-nf, the l i nk,di soonnect elay. ve -an m s tweed. rem ground through; ema on ct, 129i rel hrough; v i-. 1 1' e y a, t alternate gcon act. 8542i relay fli'l nornial contact 1'7 ofnrelaiy qLD ;h sleeve contact of.

,irecall he flashes his. switch-hook, whi ch bringsH-abqut the;;flashing of jtlie; calling supervisory'lain as is ,well known. The 'operatorhtoansyver the.recall of the called subscriber actuates the recall key RE :to connect her operatorsset to the cord conductor.- The actuation. of the recall key inresponsetothe recall of the called sub scriberopens the contacts 72,but the relay, Rtl iloes not de energize as a substitute cir- ;cuit is established from ground-at normal contact-35 of relay AT, through conductor 70, alternate contact 69 of relay AS. tobattery-and ground through the lower winding of relay'RC. The relay RC remaining enprgized-in turn holds the relay ET in its energized condition, thus keeping the bat tery busy potential from the multiple jacks ofthe calling line and this allows another operator to connect to the said calling line as a called line.

From the foregoing it is thus seen that l have provided a system wherein when the calling subscriber recalls he automatically flashes a supervisory lamp so that the same operator may seize the recall, but I still retain the feature of automatically disconnect mg the callu glin'efrom the cord circuit, when it is desired use the calling line as :1 called line p'prior' to the time that the previous connection istaken down.

4 AlthoughI hiiveshown-a. preferred em? bodimentoi 'my hvenuen for the'purpose f. u fme -id s i n my l n-y tion, Iar n awaretha't the teaturespofi lnyj inventionv are applicable to otherfs'ystenis A than that shown and many modifications and changes may be madeiby skilled in the art and I therefoie domotlwishlto limited to the exact structure but aim to cover allsuch changes aiidiiiofli' fications as come-within the spirit and scone 8c of the appended claims. Q

Having, described inventioii', ivli atfl. claim as new and desire to nnre b'v StatesLetters B-atenh isz" p 1. A telephone; system} including "git scribers telephone. line, :1 plurality of ter-.- minals for sa-id line, a link'cimiiefg ex-h tending connectipn jrom fsaid lin'e ,iinean's p ve t -a i a iee- -i ie 'su s at qi switch foriplacing a busy' po teilti alfiipon 190 i saidflarminals beforeconnectioh is iiiadeby 1 said link circuit with one, of said terminals, a supervisory signal, fors aidlink circliit, calling subscriber-controlled means for automath-ally and intermittently operating said signal. disconnect means for said link cir-I (-uit for automatically "disassoeiatiiig link rircuitand said lineymeans responsive to the connection ofthecalling end of ,-a second link circuit to one of the said 'te'ri minals for operatingsaid disconnect means,

and automatic means for 'said first link lcircnit operable when the calling stibscribpr; replaces his receiver to disconnect busy potential from said terminals to-render said terminals idle prior to the operation of said disconnect means.

2. telephone system including a'subsvrihers line. :i liul; circuit for connecting with said line, said line being provided with multiple terminals means responsive to the actuation of a substation switch for placing a. busy potential upon said terminals beftllt connection is made by said link circuit with one of said terminals, a ,second means responsive to the actuation of the sub- Stati n switch for placing am busy potential upon one of said terminals after connection has been made with one of said terminals,

disconnect means for temporarily disassoci- L20 :iling said link circuit and said line. and

el -erator-rontrolled means effective when said line is in an idle condition for operating saiil rlisconnert means.

I A telephone system including a willing [1'5 telephone line, a link circuit provided with an answering terminal for connection thereto, said line being provided with multiple terminals. means responsive to the actuation of the substation switch for placing a busy 5 a bus jpoteriti'ei'l iipoii siiid' terminals afterconnect onfrhiisfbeen ined'eiiivit'h one of sdihilinslreniig.wrmiiislyendfcr removi g fdr'siildliiilr"circliitfsubstition i the slllistat'ion ontilllsfs'sia signagesna 2 aan ssfiuuaissfileanswering-termi als for sa -iii .tlie E'siilistation ofsaid llini for'jbfierfitin said-signals and fd'riiihlbi x' "Ma "can s1 upana'ssza tereen-s n "i11id 'fo r'g suldstitiit ng ws coiul ibiisy jiotentia l t arid ais controlled at 'the said sub- 85 "subscribersilille, .a plurality foffmnltiple 121' s indifililtiplefiins'w'ring terminals for said. line finedris' controlled, it the substation f operating said signals and 40 iniifalsfn' iikicii'cint 'for *c'onnectionto said line,' "'mia'ns ie onsiveftothe connection of said 'link circuit to;said' line for removing said "firsfbusy-"potential and for substituting- .a second 'busy potential, a nil means 'con (5 trolled atthe' said substation forfrem ovirm said second busyjpoteiitial "when (liSCOTlHfretion is signaled 'foriand iorfsiibssquently replaeirig 'saidlal;tr busy potential when a recall is si 'alledfon 6. "A telfiiihbne system including -a subsci'il'iers line provided with an answering terminalfineans controlled a't the-substation of "salid line for placing a 'busv potential po n'. a ti'o'iitact of'-saiclaris we'rilng terminal. a link circuit-includingoperator ontrolled means for'remoring said busy potential aim for substituting a se ond husy potential substation controlled means for rr-ruoviw said 'fsecond 'h'usy potential and "sllhsl ll 1 ion 'controlled means for'l'eplac in'g a busy p tential upon said line While maintain ng" Said SubseiibeNs line o'peratively conncrtei to said link circuit.

7.-'Ate lephone system including a subscrib'rs telephone line-provided with "mul- I. li' cii cllit' for' miiegficn to-snd 25' was s s? n rarsssniikvsraait a'ndsub.-" "said line, means responsive to an actuation i lal,' aiiiififiieaiis'iesponsii er 1 fs'aidliiik ir'cuitto said tiple terminals: multiple line signals-for said line, substation controlled means for operating said signals-11nd for-placing a busy potential upon said multiple terminals upon the initiation of a call, a link circuit' l'irovide-il wit-h a supervisory signahand sub scriber controlied means responsive -to#-asingle actuation oi a substation 'switch for intermittently operating said link circuit sigii'al.-

A telephone system includinga subl scribers telephone-line provided with'zmnltiple terminals, multiple linesignals'fonsaid line, means responsive to'an' actuation of a sub'stationswitch' for operating said signals and for placing a inusy potential uptimsaid mi'iltiple' terminak, o link-circuitffqr extending a connection from said line, a-signnl -associated with said link circuitzand means controlled by a. subsequentunita ry actuati'on ofthe saidsubstation switch for intermitt/ently operuting said link circuit signzil. '9. A'telephone system including a subscribers telephone'line rovided with multiple terminals multipe line-signals for -9u of af'substat-ion switch for operating said signals and for placing a busy potential "upon said'multipl s terminals. 3 link circuit 'when disconnection is desired, and means for extending :1 connection from said line. a signal associated with said link circuit means for operating said link circuit srgnal for thereafter intermittently operating said link circuit signal responsive to a single actuation of said substation switch when arecall is desired.

10, A telephone system including a subscribers line provided with an answering terminal means responsive to the removal of the receiver fit the substation on said line when initiatinga (all for placing'a hus potentiel upon said answering terminal, a link circuit provided with a supervisory signal, operator controlled means for con no-"ting soiai l n irruit to saidline (or o.\'-

tending a connection therefrom. means for removing said husv potential. and means controlled by a subsequent removal of the receiver at (he said snhstntiou for eutomatially intcrmiflouflr upm'nlill r .iilil su'oervfl sory signal,

[1. A telephone system invlucliugr n sultscrihers line provided with us answeringterm nal. means responsive to the removal of the receiver at the substation on said line for placing a bus: mtential upon said answerinp terminal. :1 link circuit nrm'ielwl n'ih supervisory sign-.13 operator mmtrollwl means for rouneotin'r snirl link (i cult to said line for exlendim a connection therefrom. means for removing said husr potential and means controlled by a subse- 'quent removal of the receivernt the said SUbStZXtIOH for automatically intermittently tial upon said answering terminal, a link circuit for extending a connection from said telephone line, means for removing said busy potential, and means responsive to a subsequent removal of the receiver at the substation during the period that said link circuit is connected with said line for replacing a busy potential upon said answer mg terminal while maintaining said link circuit operatively connected to said subscribers, line.

13. A telephone system including a subscribers telephone line provided with multiple terminals, subscriher-controlled means including a switch'for placing .a busy po-.

tential .upon said multiple terminals before connectionis madewith one ofsaid terminals, other subscriber-controlledmeans for manila tosaid answering terminal, means responsive to the actuation of the substation switch ofthe said line for placing a busy potential upon said answering terminal before said link circuit is connected to said terminal, 70 a second means responsive to the actuation of the substation switch of said line for placing a,busy potential upon said answer ing. terminal after said link. circuitlias been connected to said terminal, disconnect means '75 for disassociating said link circuit terminal from said link circuit, and operator-con trolled means for automatically controlling said disconnect means when a connection is extended to saidline as a called line.

i6. A telephone system includinga sub scribers line provided ivith multiple teimi nals, a link circuit for connection to said line, means responsive to the actuation of a substation switch on said line fonplacing. a, busypotential upon said terminalsbefore said link circuit is connected to ,s aid line,

a second means responsive to theac'tiiat'ion placing a busy potential upon said; multiple terminals after connection has'been made to said line, a link circuit provided with a connection terminal for connection to one of said multiple terminals. a supervisory signal for said link circuit, subscriber-controlled means for-causing the intermittent actuation of said supervisory signal, subscriber-controlled means for rendering said line idle, a second link circuit, and means responsive to the connection of said second link circuit to another of said multiple terminals for automatically disassociating said first link circuit from said line, and for placing a busy potential upon said multiple terminals.

14. A telephone-system including a subscribers telephone line provided with an answe ing terminal. a link circuit provided with a connection terminal for connection to said answering terminal. means responsive to the actuation of a substation switch for placing a bus potential upon said terminals before connection is made to one of said terminals by said link circuit. a second means responsive to the actuation of the substation switch for placinir a bus potcntial upon said terminal after onnection but been made with one of Slld terminals b said link circu t. a su iierriwr signal, sub scrihcr-controlled means for intciinillentl controlling said supeiw'isory signal. disconnrc! means for ilifxzssociatinp said link circuit 'lllllliill from said link circuit. and 0}HIlllUl-t7(iiilllfllletl means T r unlmnnl cnlli' operating said disconnect means if). A telephone systcin including 1| ml;- scrihers tele hon-a line provided ath an rinsnoring, terminal. a link circuit provided with a connection terminal for connecting of the, substation sivitch on said line'jor placing, a busy potential on said terminals 590 after said link circuit has been connecteg to said line, a supervisory signalifor saif link circuit, subscribercontrolled meansfior operating said signal to denote a recall, electromagnetic disconnect means for dis connecting said link circuit from said line,

and o aerator-controlled means operative only if said terminals test idle for ope rat; ing said disconnect means when calling said line as it called line.

1?. A telephone system includin "a subscribers telephone line lprovidedivith mul tiple terminals, a link circuit provided with a connection terminal for connection to said line for extending a connection therefrom, means responsive to the actuation of a su station switch on said line for placing a. busy potential upon said terminals before said link circuit is connected to one of said terminals, :1 second means responsiveto the 0 actuation of a substation switch ,on said line for placing a busy potential upon said terminals after said link circuit has been connected to one of said terminals, a supervisory signal for said link circuit. subscriber-controlled means or operr-iting said signal to denote a recall and for rendering said terminals either idle or busy, and op erator-controlled means For automatically disconnecting said link circuit terminal from said link circuit and for rendering said subscriber-controlled means inoperi tire.

l8. telephonev system including a sub scriber s telephone line provided with multipic terminals and multiple line signals at the exchange. subscriber controlled means fury, operating said signals and for placing a bllS potential upon said terminals. a plurality of operators link circuits, means for pre ventinglthe. operative connection of nlore than one of said link circuits to saigl line whe n w in a call t e m a su e visory signal for said link circuit, and means re sn iye. w ia em l 0 the j eirr a h e steti ia said i e wh n rese in li ra t tlii ev n ing sa is ern qri ig la d fe plasmas y w p zd t pl ermi el t c Q-A telephon sys m including a subr' rs a e l nelinsp t r dedni h mul ile ternrinalg, substation-controlled, means q P ci g-= yn ientiel p s 'ni i tiple term nals when -ini tiat-in a call, a link circuit f or connection'to 'said line via one of its multipleterminals, a supervisory signal for said link circuit, and subscriber-coir tro ed means responsive to a single actuation of the switch hook for intermittently oper ating said snpervisory signaL,

20. A telephone system inclnidingja subscribers tele one hn'e provided with multiple termina ls, a link circuit for connection to said telephone line via one of its multiple terminals, means responsive to'tlie actuation of a substation switch on saidrline for placing a busy potential upon said terminal 3-. fore said link circuit is connected to one of said multiple terminals, a supervisor signal for said link circuit, subscriber-controlled means responsive to a single actuation of a substation switchhook for intermittently operating said supervisory signal, a1id,opc1'- ator-controlled' means for automatically di'sconnecting said subscribers line from the strands of said link circuit.

21. A telephone system including a sul scribers telephone line provided with multiple terminals, :2. link circuit for connection to said telephone line via one ofits multiple terminals, means responsive to the actuation of a substation switch on said line for plaicing: a busy potential upon said terminals before said link circuit is connected to said line, a supervisory signal for said link circuit, subscriber controlled means responsive to a single actuation of the substation switchhook for intermittently operating said supervisory signal, a sec-1 ond link circuit, and meains forautomatically disconnecting s'aid sub'scribers line from the strands of said first link circuit, said last means being responsive to the cdn: ne'ctionof said second link circuit to one of the multiple terminals of said line.

22. A telephone exchange system including a subscribers tele'phdn line having line conductors, a terminal at the central ollide in which said line conductors terminate. an,

auxiliary independent test contact for said terminal, subscribers substation switch-com trolled means actuated upon the initiation of a call for placing a busy potential upon said test contact and for removing said busy potential from said test contact upon a subsequentactuatipn or saidsubstation switch, a link circuit for connection to said line via said terminal, provided with a supervisory signal, snbscribers substation switch-controlled means for controlling the intermittentflashing of said signal, and operatoi' s controlled means for rendering subscribenwntrolled busying means ineffective and interrupting said intermittent flashing of gs'aid signal. 7 a

1 23. A telephone exchange system including a sub's'cribers telephone line terminating at the exchange in a connection terminal. an auxiliary independent test contact for said terminal, subscribers substation switch-controlled means actliated upon the initiation of acall for placinga busy potential upon said test contact and for removing said busy potential from said test contact upon a subsequent actuation of said substation switch, a link circuit connection to said line terminal rovided with a supervisory signal and subscribers substation switch controlled me'ansjfor controlling the intermittent flashing of said signal, operators controlled means for rendering saidsubsci-ibers controlled busying means ineffective, said operat'ors means being controlled by the connection of asecond link circuit to said subsc'ribers line.

. QaL A telephone system including a calling subscribers telephone line, a plurality of terminals for said line, :1 called line, a link circuit for extending a. connection from said'calling line to said called line, a recall relay for said link circuit,.an operators telephone, automatic means for connecting a'nd disconnecting said operators telephone and said link circuit, a supervisory signal for said link circuit. subscriber-controlled means for interi'nittently operating said signal, antomatic ringing means for said link circuit. said recall relay controlling a contact of said ringing means for disconnecting ringing current from said called line should the calling subscriber rrpluw his receiver before the called subscriber respimds. disconnect means for said link circuit for automaticallv (lisassociatiin said link circuit and said calling line, and means responsive to the connection of the calling end of a second link circuit to one of said terminals for operating said disconnect means.

25. A telephone system including a subscribcrs telephone line novided with a plu rality of multiple terminals. a link circuit provided with a connection terminal for connecting to one of said terminals for extend ing a call from said line to a called line, a recall relay for said link circuit. an opera tors telephone. automatic means for connect ing' and disconncctin; said operato'rs telephone and said link circuit. automatic ringing means for llulink circuit, said recall rcln mntrolling n minim-i of said ringing means for disconnecting ringing current from the called line, means'associated with said link circuit for automatically disassociating said link terminal and said link circuit, and means controllable only by the connection of a second link circuit terminal to anotherof said multiple terminals for operating said means for'disassocia-ting said link terminals from said link circuit.

26. A telephone system including a calling subscribers line, a called subscribers' line, a link circuit for connecting said callin line to said called line, a recall relay for said link circuit, an operators telephone, automatic means for connecting said operators telephone to said subscribers line, automatic ringin means for said link circuit, said recall re ay controlling a contact-ofsaid ringing means for disconnectin ringin current from said called line shoul the cal ing sub-' scriber replace his receiver before the called subscriber responds,- disconnect meansfor automatically disassociating said link circuit and said line,and operator-controlled means free'from substation" control but effective when said line is in an idle condition for op crating said disconnect means; A 5 i l 27. A telephone system including a calling telephone line, a link circuit provided with an answering terminal for connection thereto, an operators telephone, electromagnetic means for connecting and disconnecting-said operators telephone and said link circuit, a supervisory signal for said link circuit, a recall relay in said-link circuit, substation controlled means for flashing said signal, electromagnetic means-for disconnecting the talking conductors of the link circuit from the said answering terminal and for remov in the substation control of said signal, said'electromagnetic means being responsive to the connection of a second link circuit terminal to the calling line if the calling line is in idle condition, and automatic ringing means for said link circuit, said recall relay controlling a contact of said ringing means for disconnecting ringing, current from the called line.

28. A telephone system including asubscribers telephone line provided with multiple terminals, :1 called line, multiple line signals for said line, substation controlled means for operating said signals and for placing a busy potential upon said multiple terminals, a link circuit provided with a supervisory signal, a recalling relay in said link circuit, automatic ringing means for signaling a substation upon said called line, said recalling relay controlling a contact of said ringing means for disconnecting ringing current from said called line, and subscribencontrolled means responsive to a single actuation i a substation switch for llltQlllllllEllilV operating said link circuit signal.

therefrom, means for removing said busy potential, automatic ringing means for signaling a'substation upon said called line, said recalling relay controlling a contact in the circuit of'said ringing means for disconnecting current from said called line, and means controlled by a subsequent removal of the receiver at the said first substation for automatically intermittently operating said supervisory signal.

30. A telephonesystem including a subscriberstelephone line provided with multiple terminals, subscriber-controlled means for placing'a'busy potential upon said multiple' terminals beforc connection is made with said multiple terminals, :1 second subscriber'controlled means for placing a busy potential upon saidmultiple terminals after connection ismade with said multiple terminals, a link circuit provided with a connec tion terminal for connecting to one of said multiple terminals, a supervisory signal for said link circuit, subscriber-controlled means for causing the intermittent actuation of said supervisory signal, subscriber-controlled means for rendering said line idle, and means responsive to the connection of a second link circuit to another of said multiple terminals for automatically disassociating said first link circuit from said line and for placing a busy potential upon said multiple terminals, said link circuit being provided with automatic ringing means and with automatic listening.

31. A telephone system including :1 sub scrihers telephone line provided with an answering terminal, a link circuit provided with a connection terminal for connecting to said answering terminal, a recalling rcla in said link circuit, a supervisory signal, su scriber-controlled means for intermittently operating said supervisory signal. disconnect means for disassociating said link circuit terminal from said link circuit. operator-controlled means for automatically operating said disconnect means, and automatic listening means and ringing means for said link circuit, said recalling relay controlling contact of said ringing means.

32. A telephone system including a sult scribers telephone line provided with an answering terminal, a link circuit provided with a connection terminal for connecting to said answering terminal, a busy test relay in said link circuit, disconnect means for disassociating said link circuittcrminal from said link circuit, operator-controlled means free from substation control for automatically operating said disconnect means when connecting to said line as :1 called line, and automatic listening means and ringing means for said link circuit. said recalling relay controlling a contact in the circuit oi said busy test relay and also controlling a contact of said automatic ringing means for disconnecting ringing current from the called line.

33. A telephone system including a subscribcrs line provided with multiple terminals, a link circuit for connection to said. line, a supervisory signal for said link circuit, subscriber-controlled means for operating said signal to denote a recall, electromagnetic disconnect means for disconnecting said link circuit from said line, operator-controlled means operative only it said terminals test idle for operating said disconnect means When calling said line as a. called line, and automatic listening means and ringing means for said link circuit, said subscriber-controlled means controlling a contact of said automatic ringing means for disconnecting ringing current from the called line.

34. A telephone system including a subscribers telephone line provided with multiple terminals, substation-controlled means for placing a busy potential upon said multiple terminals when initiating a call, a link circuit for connection to said line via one of its multiple terminals, a supervisory signal for said link cincuit, subscriber-coir trolled means responsive to a single actua tion of the svvitchhook for intermittently operating said supervisory signal, and auto matic listening means and ringing means for said link circuit, said subscriber-coir trolled means controlling a contact in the circuit of said automatic ringing means.

:55. A telephone system including a. subsi-riber s telephone line provided with multiple terminals, a link circuit for connection to said telephone line via. one of its multiple terminals, a supervisory signal for said link circuit, subscriber-controlled means responsive to a single actuation of the Sill)- station switrhhook for intermittently aetuating said supervisory signal, operator-coutrolled means for automatically disconnecting said subscribers line from the strands of: said link circuit, and automatic listening means and ringing means for said link circuit, said subscriber-umtrolled means controlling a contact in the circuit of said auto-- matic ringing means.

36. A telephone system including a subscribers telephone line provided with multiple terminals, a link circuit for connection to said telephone line via one of its multiple terminals, a supervisory signal for said link circuit, subscriber-controlled means responsive to a single actuation of the sole station switchhook tor intermittently actuating said supervisory signal, means "For automatically disconnecting said subscribens line from the strands of said link circuit, said last means being responsive to the connection of a second link circuit to one oi the multiple terminals of said line, and automatic listening means and ringing means for said link cincuit, said SllbSCI'llJGI'vt)htrolled means controlling a contact in the circuit of said automatic ringing means.

37. A subscribers line and a telephone system having multiple connection terminals. a connecting circuit for connection to said line through one of said terminals, suhscrilier-controlled means for placing A busy potential upon said terminals prior to the said establishment of the connection to the line, a signal for said circuit, subscriberoperated means for intermittently operating said signal, and operator controlled means for disconnecting said subscribens line from said connecting circuit.

Signed by me at Chicago, county of Cook and State of Illinois, in the presence of two witnesses.

(HAS SPARKS.

Witnesses (i. A. YaNoonmvsiu,

B. OBRIRN. 

